The present invention relates to a method of mounting a boot on a cylinder such as a wheel cylinder for a vehicle brake drum and a hydraulic pressure master cylinder which pressurizes an operating liquid and supplying the operating liquid thus pressurized to the wheel cylinder in such a manner that the boot covers the opening of the cylinder hole, and to an apparatus for practicing the method.
More particularly, the present invention relates to a boot mounting apparatus with which the annular sealing portions of a boot are automatically fitted in the sealing grooves of a piston and a cylinder body from outside, and to a method of mounting a boot with the apparatus.
One example of a cylinder in which a boot is mounted on a cylinder body and a piston in the cylinder hole of the cylinder body to cover the opening of the cylinder hole is a wheel cylinder for a vehicle drum brake (cf. Unexamined Japanese Utility Model Publication (OPI) No. Hei. 4-105643).
In the wheel cylinder, sealing grooves are formed in the outer cylindrical surface of the cylinder body and in the cylindrical surface of the protruded end portion of the piston, and the annular sealing portions of a boot are fitted in the sealing grooves thus formed. In order to automatically fit the sealing portions of the boot in the sealing grooves, various apparatuses and methods have been proposed, for instance, by Examined Japanese Patent Publication No. Hei. 3-61859, Unexamined Japanese Patent Publication (OPI) No. Hei. 3-208528, and Examined Japanese Patent Publication No. Hei. 2-28015.
The apparatus or method disclosed by the aforementioned Examined Japanese Patent Publication No. Hei. 3-61859 is of the outside fitting type that the annular sealing portion is fitted in the sealing groove from outside. The apparatus or method disclosed by the aforementioned Unexamined Japanese Patent Application (OPI) No. Hei. 3-208528 is of the inside fitting type that the annular sealing portion is fitted in the sealing groove from inside. That, the two prior art apparatuses and methods are applicable to the fixing of only one of the annular sealing portions.
On the other hand, the aforementioned Examined Japanese Patent Publication No. Hei. 2-28015 is applicable to the fixing of both of the annular sealing portions. However, the prior art is still disadvantageous in the following point. The prior art is the combination of the outside fitting type and the inside fitting type that one of the annular sealing portions is fitted in the sealing groove from outside, and the other is fitted in the sealing groove from inside. Hence, it cannot be applied to a cylinder such as a wheel cylinder for a vehicle drum brake in which both of the annular sealing portions are fitted in the sealing grooves from outside. Therefore, heretofore the annular sealing portions are manually fitted in the sealing grooves, taking time and labor.